Chair-adjusting mechanism



April 20, 1954 c. E. CUSHMAN 2,675,861

CHAIR ADJUSTING MECHANISM Filed Nov. 17, 1950 2 SheetsrSheet 1 CLIFFORDE. CUSHMAN,

INVENTOR.

A TTORIVEV.

April 20, 1954 c. E. CUSHMAN CHAIR ADJUSTING MECHANISM 2 Sheets-Sheet 2Filed Nov. 17' 1950 CLIFFORD E. CUSHMAN,

INVENTOR.

ATTORNE'K Patented Apr. 20, 1954 CHAIR ADJ'UsTING w Siamese-1m; m m

Appncetionmvmiier 17, 1956, SerisLNo 196,209

Tfiisinventionrelates to adjustabl'me ha mcai structur anduparticularly.to improved pos'ition adjusting; mechanisms er'riplo'yed therein.,Tfi'e} 16 Claims: (01. Is s- 1 st) invention'possesses particularutiIityinjconnec V t gfln withsrecliningl chairs havi k and m'r hisreason. it described in det inT ee non therew The 'sitio'n adjiistingmechanism of Ithisinventio'n is an improvement over one of thesedeseribed andclaimed in} copending patenti'applioa 1N6. 4,34'1jfi1ed lbymeJanuaz-y T'2i6;194'8',' ent N6. 2j579,305'. In that application thereis gi .dscribedie special 'form of position adjustingjnechamsm of thecantingc-lver typethat employs awsmooth rod andcanting leaves ,f-fiengageable therewith as abrake elements for locginglthe. beck'of a. chairina predetermined tilted =position'.. When locked these brakeelementslhgol d the back of a chairset in a predtrminedfpositjion solong as the .compression and extension loads applied-Ito the positionadjusting mechanism li'e belowcorresponding, .prede'te'rmined limits"lfi that'type of position adjusting. mech' v ism suitablecontrol meansereprovided foneleasing the -grip. ofl the canti'rig. iayewn to permitthe chair occupant to :mo'veme acle from oneposition to another, In.-the chair back in a newflposi tionthe an ans .is manipulsted toC'ausmthecantiiig s'"togrip =the rod at th new position so ais ck c theposition adjusting-H mechanism.

' prai'c itice in employ in'g that po'sitiizin adliils'iiiiig.-

mechanism, it has-been found that the cantin'g.

- leves often grip 1 the rod so gqu ickly that' a cettain. amount ofimpleasant. shock isvexpe ienced if the chair is -sti11 'in-motion atthetimeth'at theca'ntinglleaves 'engagethe rod c .7

Accordingly, it is one of: the objects .of the biiesent invention toprovide an a-dj usteblech'ali r with an adj iista'ibleposit'ioningedeviceof the fcanting} 6" lever type vthat cushions theshock of locking when thepositioningf deviceis ldckdwhil 1511cchflirbeckis-inmotionr I Another object of the invention ismpmvme siichan adjustable positioningsdvice whichhofds the chair' lockedagainst-relatively. laLrge rear ward-tilting forcesJbnhwmc'h permits theback member to be moved iloLforward-tiltiiigl forces exceeding areltivlylow Vahie.

Another object of the invention is.to provide a position"'adjiistifighichamsnfof the (tintin l r Wpein'which the gi'iiroffth"ecanting mem her upon the 'rod *membefiismppnd gradually diiiin'glo'eldng. 7 e 1 v I nother obieot cr me invention is to provide tioan adjustable lpcsitmngmecnamsm Qftl'ie canting l'ver {typeWhidh"'is"'0'f light weight and'of rugged inexpensive construction.

therodmember of a 'canting le'v'er'type positiofilockis designed'to beyieldagble or compressibie' firansversjeiyso, that the rod member iscom:

presses s1ight13 when 'the 'c' anting lever bits .into itiza'uri iockingpcc'tion. In the particular em:

b ocliinent, of the invention il lhstfeitefl herein .ithe y eiai'ngaction ofthej rod memberis provilded'aby constfueting the ma member? intwo parts,- namelyge; shaft member "and "a; sleeve member whichm etelescopicallg ai 'remged; vryfeffective cilshiofiing "effects" afeobtainedwith such "afiarngeme m by mpioymg a shaft member of tubuieo'n'struo't anew split or' divided "sleeve ya i'o'u's'imesn's by'which'the de- 20 with the attainment of other desired results mean il' igdevice;

as cdntrdnable adjustbl' positioning mechanism for a 'tiltable chair iare set j'forth'in the {following detailed descfiption of one embodimentof the invention.

Inthe;"'(irtmrings wherein'theisame numbers in the severe-1 v e 's'refiiiesentlikeparts z Figfif'e' 1 "is "a; fragmentary "view of- .a,tiltabl'e chair incorporatingthe invention;

v v 2 1 :r agmentaryview' ShOWinQthe contfol n'fo'flocking and'iel'easinthe position;

S i. "side elevations; view, partly, broken o the 'position 'ad'jiistiiig mechanisi'nf 1s ardetail'ed sectional view of 'theposidii'lstifig'fi echanism';

i sect'i(na;1View taken on" the plalne nustmted in Fig; 1 the Chair l0acoinblish' the objects ofvgt h'e Dresentiriven- 7 fefratgmentary "viewssnowin iiigt-ameipasim rsm mechanism 2u'"com-' 3 28 in order to efiectthe locking and the releasing of the position lock 22.

The position lock 22 comprises a canting lever in the form of a lockingcollar 30 that encircles a rod structure 3| that comprises a splitsleeve member 32 and a shaft member 34 telescopically arranged. Theshaft member 34 is of hollow tubular construction and is provided with apair of slots 36 vextending lengthwise thereof and providing atransverse or radial elongated opening therethrough. The slots 36 are ofequal length and terminate somewhat short of the ends of the shaftmember 34 and are sometimes hereinafter referred to as a single slot. Atang 38 is firmly secured to the front or outer end of the shaft member34 and extends outwardly therefrom. The tang 38 is suitably pivotedabout a horizontal axis by means of a horizontally ex-' tending pin 40secured to the stationary support. member IS. The rear or inner end ofthe shaft member 34 is capped by means of a disk 42.

The sleeve member 32 is in the form of two parallel rod members 44 ofconvex arcuate configuration separated by slots 45a and 45b. The two rodmembers are firmly secured to a tang 46 which is pivotallysupported on ahorizontal pin 48 at the lower end of the frame 24 of the back memberI2. A spring-loaded catch 50 is employed to hold the tan 4B in positionon the pin 48. The front ends of the rod members 44 are secured togetherby means of a pin 52 that extends through the shaft slot 36.

The sleeve member 32 and the shaftmember 34 are of circularcross-section and are frictionally engageable and they are machined andtreated to provide a pair of nongalling long-wearing contactingsurfaces. With this arrangement the rod structure 3! is compressed whenthe back member I2 of the chair is tilted rearwardly and is extendedwhen the back member l2 of the chair is raised to its upright position.Dur-,

ing compression and extension of the rod member 22 the sleeve member 32and the shaft member 34 move longitudinally in sliding frictionalengagement. j

Therange of movement of the sleeve member 32 and the'shaft member 34 isdetermined by the length and position 'of thes1ot'36. The pin 52 engagesthe front end of the slot 36 in the most compressed positioncorrespondinto the most rearward tilted position of the "back member l2. The pin 52engages the rearward end of the slot 36 in the upright or most forwardposition of the back member l2.

'The locking collar 30 is pivotally supported at the outer end of apivot arm 54 that is secured to the shaft member 34 at a positionaligned with one of the slots 45a of the split sleeve member 32; Thepivot arm 54 is itself pivotally attached to the shaft member 34 bymeans of a finger 56 that projects loosely through a short slot 58 inthe shaft member34, thus permitting the outer ends of the locking collar30 to move laterally relatively to the axis of the sleeve member 32."The pivptarm '154 is sufli'ciently. narrow tov permit the sleeve member32 to move past it freely during .extensionand compression. A notch 59just above the finger 56 and a straight edge 60 at the rear end of thefinger 56g$erve to retain the pivot arm 54 in the slot 58 without,however, interfering -.with slight pivotal. movement of. the pivotarm54. The pivoting of the locking collar 30 on the pivot arm 54 is.accomplished by means of a pin 62 that projects through the outer end ofthe pivot arm 54 and through the opposite sides of a U-shaped bracket 64projectin outwardly from the lockin collar 36.

The locking collar 30 is arranged to be canted forwardly about the pivotpin 32 so that walls 66 on opposite sides of the aperture 68 of thelocking collar are engageable with the outer surface of the sleevemember. 321at thezec'lges of the slots 45a and 451). In practice, theaperture 68 is of oval or elliptical configuration having a minor axis Xjust slightly greater than the outer diameter of the sleeve member 32and a major axis Y of somewhat greater length. With this arrangement theouter edges of the rod members 44 intermediate the slots 45a and 45bengage the sidewalls 61 of the aperture 68 and the slots 45a and 45b areslightly narrowed as the locking collar 30 bites into the sleeve member32.

A locking lever 76 is pivoted on the other side of the rod member 22from thepivot arm 5%. The pivotal connection of thelocking lever' 10 isaccomplished by means of a pivot pin 12 projectin therethrough and alsothrough the opposite arms of a second U-shaped bracket 74 extending fromthe locking collar 30 on the opposite side thereof from the first -U-shaped bracket 64. H

A straight arm' 76 at the inner end of the locking lever 19 projectsthrough a'window 18 in the locking collar and through the adjacentsleeve slot 45b and into a short slot 8!l formed in the shaft member 34.A tension spring 8 2 is attached at one end to the outer end of thelocking lever 13 and at the other end to the shaft member at a positionaligned with the sleeve slot 451). The tension spring 82'normally drgesthe outer end of the locking lever 10 forviiardly and counterclockwiseof the pivot pin '12. During this action the inner arm 76 of the lockinglever 16 engages the rear end 84 of the slot 80, thus permittin thelocking lever to pivot about this point thereby urging the lockingcollar 30 counterclockwise and forcin the walls 66 into grippingengagement with the sleeve member 32. A shaft 86'extends transverselythrough the shaft-member 34 ina plane common with the major axis Y'ofthe collar member 30. "The shaft 86is journalled to the Shaft member 34and is rotatable therein. A crank 33 atone end of the shaft is connectedby means of a cable 92 to the endof the control lever 26 that isconcealed within the chair arm 28. A crank 34 at the other end of theshaft 36 is connected with the outer end of the locking lever 76 bymeans of a link 96-including a turnbuckle 98. With the arrange mentillustrated downward movement of the ex posed end of the control arm 26causes the shaft 86 to rotate and to operate through the linkagecomprising the crank 94 and the link 96 to push the outer end of thelocking lever 16 clockwise and in opposition tothe force of'thespring82; When this occurs the inner arm 16 first engages the forward end ofthe slot 33 causing" the locking lever to pivot at this pointand'to'move the locking collar 30 clockwise. As the locking collar 30ismoved clockwise about'the pivot pin 62 the grip of the aperture walls66. on the sleeve member 32 is released. V i v j In order for the seatoccupant to move the back member l2 of thechair, the control lever 26 ispressed downwardly causing the grip of the locking" collar 30 of thesleeve member 32fto'be re leased. With the grip of the locking-collar 30released i'ms an easymatterto'tilt theback mm: A

ber l 2 forwardly on rearwardly :to any desired positions During this:actioni'the shaft member the -locki nggleverlll counterclockwise andtocause the-locking collar 30'- to grip the sleeve member 32.Ifrthe-back'member: :l 2 is in :motion at this time, 4 th'eshockof-locking is-cushionedtoa large extent by virtue o'f thevfact that thelockin'g collar compresses thesleeve member 32- and the' shaft memher-3H 1 1 As compression-, spring: 1034s arranged within the sleevememberbetween-the lane 46 andthe disk 42. This icompression spring actsto-exte'nd: the -rod"member= 2 2- 'when the-gripof the locking collarismeleased}: thus aiding the: occupant of the lchair to: tilt the backmember I 2 forwardly. Though? the spring a l also'resiststhebackwardtilting of the back. member, the-strength 'ofthe springis not-sogreat as to seriously interfere with is such action. As the back memberl2 is -forced rearwardly while'the lockingdevice- 22 is in lockedcondition; a. compression force is applied to the opposite ends a of therod member 2 2 tendingto forcerthe: shaft membera34' into the sleevemember 32:. As thisoccurs the-locking collar 36 bites'furthen-into the.outerzsurface of the sleeve member 32' compressing} it against the shaftmember -34 andcompressing boththtasleeve member 32' and the shaft member34 as the backward force'applied to the back member 12 is'increa'sed-Thus, the greater the backward itilting force applied tothe-"backxmember J 2 the stronger is the forceapplied by the lockingcollar to therod member 22. z "Finallyyhowever, when the rearwardtiltingforce applied to the "back member 12 exceeds a predeterminedrelatively highx-valu'e, the shaf-t member 34 commences to slip .with inthe sleeve member 32 and: the slipping .is resisted @by the frictionalforce between the sleeve member 32 and the locking collar 30 and'also bythe-frictional force between thesleeve member 32andthe-shaft member, 34;Inpractice,: itqis found that -the value of the. load limit against:whichrthe locking device; 22 is :capable of. holdingsbefore slippingdsdetermined inpart by the transverse stiffness ofthe shaft member 34and-the sleeve member 32; Thus, for example, the limit ofloadzwhi'ch-can be held-bytheglocking device 22 in-compression may beincrease'd byxincreasing the thickness =ofthe wall of the; tubular shaftmember 34.

As-theback member. I2 is" forced forwardly" while-the: locking: device22 is in lockedcondition; a tensionforce is applied :tothe opposite endsof the-rod member 22 tending; to" draw. the shaft; member 34 outotthe-sleevemember 321 As this occurs; the bite -of thewlockingcollar 30on the outer surface of the sleeve member :32 and theforce between thesleeve member 32 and the shafti member 34: is? slightly relieved: moreand moreas therforward .tilting :force applied :to the back member I 2is increased; During this action, how ever; the tension spring 82 keepsthe locking col lar. urgedagainstthe sleeve member 32 in lookingengagement therewith; Finally, however,- when the forward tilting forceapplied to the back-- member l2 exceeds a predetermined relatively low.value, the shaft member 34 commencesio slip within the sleeve member 32and-the slipping islfresisted by thefrictional force between the sleevemember 32 and the 1 locking collar 30 and changes which will also by tnerrictienar iorcemetween thesieeve member *3 2' and the-"shaft member 3t;

Tfi' sti" netherirtension fdrces againstwhi 1 1 I1 is; capable ofholding- S determined in with "the streng't-herme tension spring 82 andin -p'ar by thedevefa'ge of the lock lever J0" amioftliei glockilig'ringd05 By setting the threshold at which s1ippi ng' *-mayoecurat aconveniently 10w va'l-meflt becomes possiblefora person to tilt tlie'back member l 2 "upwardlyby means er ardrwardly exerted force applied tothe upper end ofl 'the ba'elt memberevefnthon'ghthe" 3 control lever-16i's iri lo'eked position arid-even though the chair-m'occupied Fromtli'e reregemg descriptionof the iriveri tion -it -is readily seen tliat'a--' posi-tion--adj ii'sti'ng mechanism mas -been providedwhich-iscapableof- 'cushionin shoek during the *lockingaction main'ing cked'against a widerange of for'ces exerted m one"- direction thereon below ra 'rela--- tively larg'e load limit but is -'capable on-being readilyadjusted by relatively small forces exerted in the opposite direction--above a relatively-srr'fall- 1oad -liiniti a Whilethe invention hasbeen described with particularreference to-its applieati'on'to-a reel mgchair-, it will be. under-stood what it also be applied tootheristriicthres" arrangements inwhich it is desired to lock 5 two mainmembers in predetermined relative positions; while m y invention hasbeen described witli= reference tothe employment of" a sleeve-utilizinga pairpf slots that separate two rowmembers, more-slots may be-employed-= if desired but? in any eve'nt some 'of the' adv a nltfig'csof 1 my invention may be obtained by employing a sleeve provided withonly a single slot! gum; while- =m y-invention has been described with lreferenceto a "-rod strifeture'em'ploying-a shaftfnemberthat-telescopically engages a split 'sleevemember; it will be clear thatother rod structures-may be employed' and some of l the advantagesof vthe invention still be obtained. Thus; altliough" only one particulanembodiment of the invention has been spec'iflcall-y v disclosed herein,-it apparent; that 'the inven-" tion-is not limitedth retobut is capableofa wide variety of mechanical embodiments: i Imadditior'f themodifications mentioned 51 above, var-ions flw -readi1y suggest them-*selvesto those skilled in the artmay bemade in the material, I? form,detailsof construction" and: arrangement of the'elementswithoutde'palrt' ing nom the" sp 1 of-jthe lnventionp Inasmuch as ne f regoin 1and -many: other changes'may be'im'ade" while still emplo -mg Nari ous"features ofthe invention," it isto be under stood that the specifi 'tion'herein is-illustrative only and that ref is to-be had to the appendedclaims for' a definition-of the-limitsof the invention?- The inventionclaim'ed'is: i

1.- In-"an-adjustabl'e chair comprising aspair of relatively movable:seat" members; namely; -a sup-r port meziiber and a tiltab'le.back'm'ember; the im-v provement which comprises an adjustable posi--.tion lock for-moldingsaid back member set in a predetermined tiltposition;'said adjustable posi z tien: lock comprising a pair" of-mutually spacedparallelrod": members connected' as a 5 unit *with one?of =said" seat members; said" unit 'having' "a transverse:compressibility large compared 1 with its longitudinal---compressibility, and canting means connected with the other of-- said-seat members, said' canting means having; opposite ae'z aei.

walls frictionally engageable with the surfaces of the respective rodmembers, said rod members being movable lengthwise relative to saidcanting means, resilient means applying a force to said canting means tourge said walls against said surfaces whereby longitudinal movement ofsaid rod members relative to said canting means is resisted, and meansfor reducing the force of said resilient means to release the grip ofsaid canting means on said rod members.

2. In an adjustable chair comprising a pair of relatively movable seatmembers, namely, a support member and a tiltable back member, theimprovement which comprises: an adjustable position lock for holdingsaid back member set in a predetermined tilt position, said adjustableposition lock comprising a split rod member connected with one of saidseat members, said split rod member having a transverse compressibilitylarge compared with its longitudinal compressibility, and a cantingmember connected with the other of said seat members, said cantingmember having an aperture therein, said split rod member being movablelengthwise through said aperture, the walls of said aperture beingfrictionally engageable with opposite surfaces of said rod member,resilient means applying a force to said canting member to urge saidaperturewalls inwardly against said surfaces of said rod member wherebylongitudinal movement of saidrod' 1 member through said aperture isresisted, and means for reducing the force of said resilient means torelease the grip of said canting member on said rod member. v

3.. In an adjustable chair comprising a pair of relatively movable seatmembers, namely, a support member and a tiltable back member,the-improvement which comprises: an adjustable position lock for holdingsaid back member set in a predetermined tilt position, said adjustableposition lock comprising a rod structure connected with one of said seatmembers and canting means connected with the other of said seat members,said rod structure having a transverse compressibility large comparedwith its longitudinal compressibility, said canting means having anaperture therein, at least part of said rod structure being movablelengthwise through said aperture, the walls of said'aperturebeingfrictionally engageable with surfaces on the opposite sides of saidpart of said rod structureresilient means applying a force to saidcanting means to urgesaid walls inwardly against said surfaces of saidrod structure whereby longitudinal movement of said rod structurethrough said aperture is-resisted, and means for reducing the force ofsaid resilient means to release the grip of said canting means on saidrod member. l

Y 4. In an adjustable chair comprising apair of relatively movable seatmembers, namely, a support member and tiltable back member, theimprovement which comprises: an adjustable position lock for holdingsaid back member set in a predetermined tilt position, said adjustableposition lock. comprising a shaft member connected with one of saidseatmembers and a split sleeve member connected with the other of saidseat members, said sleeve-member telescopically engaging said shaftmember, canting means pivot ally supported on said shaft member, saidcanting means having an aperture therein, said sleeve member beingmovable lengthwise through said aperture, 'the walls" of said aperturebeing fric tionally engageable with opposite external surfaces of saidsleeve member, resilient means for 8. urging said aperture wallsinwardly against said surfaces of said sleeve member wherebylongitudinal movement of said sleeve member through said aperture isresisted, and means for reducing the force of said resilient means torelease the grip of said canting means on said sleeve member.

5. The combination described in claim 4 wherein said shaft member is ahollow tubular member.

6. An adjustable position lock for holding a pair of members set inpredetermined relative positions comprising: a pair of mutually spacedparallel rod elements adapted for connection as a unit with one of saidmembers, said unit having a transverse compressibility large comparedwith its longitudinal compressibility, and canting means adapted forconnection with the other of said members, said canting means havingopposite walls frictionally engageable with the surfaces of therespective rod elements, said rod elements being movable lengthwiserelative to said canting means, and means for urging said walls againstsaid surfaces whereby longitudinal movement of said rod elementsrelative to said canting means is resisted.

7. An adjustable position lock for holding a pair of members set inpredetermined relative positions comprising: a rod structure adapted forconnection with one of said members and canting means adapted forconnection .With the other of said members, said rod structure having atransverse compressibility large compared with its longitudinalcompressibility, said canting means having an aperture therein, a partof said rod structure being movable lengthwise through said aperture,the walls of said aperture being frictionally engageable with surfaceson the opposite sides of said part of said rod structure, and means forurging said walls inwardly against said surfaces of said rod structurewhereby longitudinal movement of said rod structure through saidaperture is resisted.

- 8. An adjustable position lock for holding a pair of main members setin a predetermined relative position comprising: a shaft member adaptedfor connection with one of said main members, a split sleeve memberadapted for connection with the other of said main members, said sleevemember telescopically engaging said shaft member, canting meanspivotally connected to said shaft member, said canting means having anaperture therein, said sleeve member being movable lengthwise throughsaid aperture while the walls of said aperture are frictionally engagedwith opposite external surfaces of said sleeve member, and means forurging said aperture walls inwardly against said surfaces'of said sleevemember whereby longitudinal movement of said sleeve member through saidaperture is resisted.

9. A position lock as defined in claim 8 wherein said shaft member has atransverse compressibility large compared with its longitudinalcompressibility.

10. In an adjustable position lock for holding a pair, of main membersset in predetermined relative positions, a shaft member adapted at oneend for connection with one of said main members, a sleeve membertelescopically engaging said shaft member and adapted at one end forconnection with the other of said main members, said sleeve memberhaving a slot extending lengthwise thereof, a pivot arm extendingoutwardly from said shaft member at a position aligned with said slot,and canting means pivotally supported at the outer end of said pivotarm, said flengthwise between said walls.

" I 11. In an adjustableposition,lock:foriholding 'a pair'of mainmembers set in a predetermined :relative position, a tubular memberadapted at Jone send for connection with one of said main (0 members, asleeve member telescopically engaging said tubular member externallythereof and adaptedat one en'd'for connection with the other of saidmain members, said sleeve member having a slot extending lengthwisethereof, a pivot. arm

extending outwardly from saidstubular'member ata position aligned withsaid slot, and canting means pivotally supported attheouter end of saidpivot arm, said canting 'means having a pairof walls disposedrespectivelyon opposite sides of i said tubular member'and said sleevemember, said walls being adapted to-engage the outer surfaceof saidsleeve member, said sleeve member being-movable lengthwisebetween saidwalls.

12. In an adjustable position lock for holding a pair of main membersset in a predetermined relative position, a shaft member adapted at oneend for connection with one of said main members, a sleeve membertelescopically engaging said shaft member and adapted at one end forconnection with the other of said main members, said sleeve membercomprising a pair of sleeve elements separated by slots extendinglengthwise thereof on opposite sides thereof, a pivot arm extendingoutwardly from said shaft member at a position aligned with one of saidslots, canting means pivotally supported at the outer end of said pivotarm, said canting means having an aperture therein encircling said shaftmember and said sleeve member, said sleeve member being movablelengthwise through said aperture, and a locking lever pivotallyconnected to said canting means on the opposite side of said sleevemember from said pivot arm, the inner end of said locking lever beingpivotally connected with said shaft member at a position aligned withsaid other slot. I 13. In an adjustable position lock for holding a pairof main members set in a predetermined relative position, a shaft memberadapted at one end for connection with one of said main members, asleeve member telescopically engaging said shaft member and adapted atone end for connection withthe other of said main members, said sleevemember having a slot extending lengthwise thereof on opposite sidesthereof, a pivot arm extending outwardly from said shaft member at aposition aligned with said slot, canting means pivotally supported atthe outer end of said pivot arm, said canting means having an aperturetherein encircling said shaft member and said sleeve member, said sleevemember being movable lengthwise through said aperture, means including aspring applying a force to said canting means for urging the Walls ofsaid aperture against the outer surface of said sleeve member wherebylongitudinal movement of said sleeve relative to said canting means isresisted, and means for reducing the force applied by said spring torelease the grip of said canting means on said I sleeve member. p

14. An adjustable positionlock for holding a pair of main members set inpredetermined relative positions comprising: a shaft member adapt-c edat one end for connection with one of said main members, a sleeve membertelescopically engag :ing said shaft'member and adapted: 'at oneaend forconnection with the other of'said main. mem- V-bers; saidsleeve-member'comprising apair'of sleeve elements separated by slotsextending lengthwise thereof on opposite sides thereof, a

pivot arm extending outwardlyf-rom' said. shaft member at a positionaligned with one of said slots, canting means pivotally supported" atthe outer enduof said pivot arm,.said canting means having an aperturetherein encircling said shaft member and said-sleeve member, saidsleevermem- .ber beingmovable lengthwise through said aper--forzurging'the walls of said aperture inwardly against the surfaces ofsaid sleeve member whereby longitudinal movement of said sleeve memberthroughsaid aperture is resisted, a rotatable shaft extending throughsaid shaft. member, anda linkage interconnecting. said locking leverwith said rotatable shaft for: moving saidlocking-lever in opposition tothe force exerted thereon by said resilient means to release the grip ofsaid canting means on said sleeve member.

15. An adjustable position lock for holding a pair of main members setin predetermined relative positions comprising: a shaft member adaptedat one end for connection with one of said main members, said shaftmember bein divided lengthwise throughout a substantial portion of itslength by a shaft slot extending transversely therethrough, a sleevemember telescopically engaging said shaft member and adapted at one endfor connection with the other of said main members, said sleeve membercomprising a pair of sleeve elements separated by a pair of sleeve slotsextending lengthwise thereof on opposite sides thereof, a cross memberextending through said shaft slot and securing the free ends of saidsleeve elements together, the

ends of said shaft slot acting as stops to limit the range of relativelongitudinal movement of said shaft member and said sleeve member, acompression spring enclosed by said sleeve member for urging said shaftmember and said sleeve member apart into an extended position, a pivotarm extending outwardly from said shaft member at a position alignedwith one of said sleeve slots, canting means pivotally supported at theouter end of said pivot arm, said canting means having an aperturetherein encircling said shaft member and said sleeve member, said sleevemember being movable lengthwise through said aperture, and a lockinglever pivotally connected to said canting means on the opposite side ofsaid sleeve member from said pivot arm, the inner end of said lockinglever being pivotally connected 'with said shaft member at a positionaligned with the other sleeve slot.

16. An adjustable position lock for holding a pair of main members setin a predetermined relative position comprising: a shaft member adaptedat one end for connection with one of said main members, said shaftmember being divided lengthwise throughout a substantial portion of itslength bya shaft slot extending transversely therethrough, a sleevemember telescopically engaging said shaft member and adapted at oneendfor connection with the other of said main members, said sleevemember comprising a pair of sleeve elements separated by' l l sleeveslots extending lengthwise thereof on opposite sides thereof, a pivotarm extending outwardly from said shaft member at a position alignedwith one of said sleeve slots, a cross member extending through saidshaft slot and securing the free ends of said sleeve elements together,the ends of said shaft slot acting as stops to limit the range ofrelative longitudinal movement of said shaft member and said sleevemember, a compression spring enclosed by said sleeve member for urgingsaid shaft member and said sleeve member apart into an extendedposition, canting means pivotally supported at the outer end of saidpivot arm, said canting means having an aperture therein encircling saidshaft member and said sleeve member, said sleeve member being movablelengthwise through said aperture, a locking lever pivotally connected tosaid canting means on the opposite side of said sleeve member from saidpivot arm, the inner end 01 said locking lever being pivotally connectedwith said shaft member at a position aligned with the other sleeve slot,a tension spring connected between the outer end of said locking leverand the walls of said aperture inwardly against the locking lever withsaid crank for moving said the outer end of said shaft member forurging25 looking lever in opposition to the force exerted thereon by saidspring to release the grip of said canting means on said sleeve member.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,948,991 Molly Feb. 27, 1934 2,319,743 Morey May 18, 19432,329,932 Nelson Sept. 21, 1943 2,469,716 Di Santi May 10, 19492,580,924 Turner Nov. 21, 1950 FOREIGN PATENTS Number Country Date15,645 Great Britain July 31, 1905

